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Friday, October 23, 2015

Innovations in road construction: Summer 2015

A fibreglass grid is installed on Sarcee Trail S.W.

Calgary is a city of changing climates, which
can cause some roadways to deteriorate more quickly than others. While asphalt
is a durable and economical material when it comes to road construction,
maintenance problems occur when cracks form within the base layers of the
roadway and are reflected up into the top layers. These cracks form due to a
number of reasons, including very low temperatures, the freeze-thaw cycle,
moisture penetration and traffic fatigue.

To keep Calgarians on the move, this summer
The City piloted a pair of new projects aimed at improving the service life of
our roadways and reduce lifecycle costs.

The first of these projects was a
fibreglass grid system. The grid is placed between the base layer and the top layer
of the asphalt. The potential is that the fibreglass grid should decrease cracking
that occurs over time on the top asphalt layer of the roadway, and the grid will
also help strengthen high use roads to prevent ruts and fatigue cracks from
forming.

A close-up of the fiberglass grid.

In this particular case, The City used a
grid that was a composite (with a nonwoven polypropylene material) which will
also serve as a protective barrier against moisture penetration. This major
road rehabilitation, including the fibreglass grid and drainage improvements, was
installed on a one kilometre section of northbound Sarcee Trail S.W. north of
Richmond Road S.W. The grid was also installed on 101 Street S.W. between
Highway 8 and 17 Avenue S.W.

The second pilot used this summer was fibre
reinforced asphalt, which was installed on southbound Shaganappi Trail N.W.
between 16 Avenue N.W. and 32 Avenue N.W. Small batches of synthetic fibre are
added to asphalt during the mixing process. This helps to increase the
structural capacity of the asphalt by making it stronger in turn creating a more
durable asphalt top layer that is more resistant to daily wear and tear.

The City will continue to monitor both
pilots over the course of their service life by comparing them with roadways of
similar age and traffic counts.